Cognitive decline due to dementia is a significant threat to the health and well-being of many older adults. As a consequence of its progressive nature, dementia inevitably leads to devastating declines in quality of life. Cognition- focused behavioral interventions which target compensatory brain mechanisms in order to improve cognitive performance have been tested in this population with promising results; researchers have yet to address why some individuals are better candidates than others. The proposed research will extend scientific knowledge regarding cognition-focused interventions by investigating the moderating effect of personality on a cognition-focused intervention in individuals with dementia at high risk for accelerated cognitive decline. The specific aims of the proposed study are as follows: 1) To test the moderating effect of personality traits on the relationship between a cognitive stimulation intervention and improvement in five domains of cognitive function (attention, memory, orientation, executive functioning, and abstract thinking) during a period of abrupt cognitive decline; and, 2) To test the moderating effect of personality traits on engagement in the intervention during a period of abrupt cognitive decline. This research will utilize a portion of the sample currently participating in a randomized clinical tria testing the effectiveness of individualized cognitively stimulating activities. Subjects are recruied from five nursing homes in Pennsylvania with post-acute care services for rehabilitation following hospitalization. Those enrolled during a two year period, or an estimated 120 total subjects, will be included in the proposed study. All subjects are screened for the presence of mild to moderate dementia as well as the presence of delirium, a state of acute confusion characterized by inattention. Acute confusion in an already cognitively vulnerable population provides an opportunistic model for viewing the effects of the intervention, including the influence of moderating factors, during the course of rehabilitation. Eligible subjects are randomized to treatment and control groups. The intervention consists of a variety of individually tailored cognitively stimulating recreational activities which are delivered for 30 minutes a day for up to 30 days; the control group receives usual care. The Principle Investigator of the proposed study will collect personality assessment data using the informant version of the NEO Five Factor Inventory, a well-established and commonly used instrument based on the five factor model of personality. Cognitive function in the five targeted domains will be measured each day in both groups. Engagement in the intervention will be measured as both time on task and level of participation. A linear mixed-effects model will be applied for data analysis. Each of the five personality traits will be tested independently for a statistically significant moderating effect on each domain of cognitive functioning, as well as separately for a moderating effect on engagement in the intervention. Interactions between multiple personality traits will also be considered within the model. Existing research has not investigated the potential moderating influence of individual characteristics on the treatment effect of cognitive stimulating activitiesin individuals experiencing cognitive decline. The proposed research will address that critical gap and help build a strong foundation for tailored cognition-focused intervention research.